Embodiments of the present invention related to medical devices and methods, and in particular to cardiac ablation systems and methods.
Atrial fibrillation (AF) is a common clinical condition, and presents a substantial medical issue to aging populations. AF is costly to health systems, and can cause complications such as thrombo-embolism, heart failure, electrical and structural remodeling of the heart, and even death.
For many years, the main treatment for atrial fibrillation (AF) involved pharmacological intervention. More recently, the focus has shifted toward surgical or catheter ablation options to treat or effect a cure for AF. The ablation techniques for producing lines of electrical isolation are now replacing the so-called Maze procedure. The Maze procedure uses a set of transmural surgical incisions on the atria to create fibrous scars in a prescribed pattern. This procedure was found to be highly efficacious but was associated with a high morbidly rate. The more recent approach of making lines of scar tissue with modern ablation technology has enabled the electrophysiologist or cardiac surgeon to create the lines of scar tissue more safely. Ideally, re-entrant circuits that perpetuate AF can be interrupted by the connected lines of scar tissue, and the goal of achieving normal sinus rhythm in the heart may be achieved.
Triggers for intermittent AF and drivers for permanent AF can be located at various places on the heart, such as the atria. For example, where triggers or drivers are located near the pulmonary veins, it follows that treatment may involve electrical isolation of the pulmonary veins.
Certain cardiac surgical procedures involve administering ablative energy to the cardiac tissue in an attempt to create a transmural lesion on the tissue. However, in some cases such methods may not be optimal due to the formation of incomplete lesions, which do not effectively create a conduction block in the tissue. Relatedly, some techniques may not provide the desired positioning of an ablation element relative to the tissue which is to be treated, or may only provide complicated and expensive approaches that attempt to maintain the desired positioning. For example, some proposed techniques cannot adequately apply ablation to the moving tissue of a beating heart. Hence, there continues to be a need for improved systems and methods that can simply and effectively deliver ablative energy to patient tissue in a uniform and reproducible manner.
Although these and other proposed treatments may provide real benefits to patients in need thereof, still further advances would be desirable. For example, it would be desirable to provide improved systems and methods for guiding and navigating various mechanisms that are used in endocardial ablation procedures. Embodiments of the present invention provide solutions that address the problems described above, and hence provide answers to at least some of these outstanding needs.